A variety of instruments are commonly used in modern society. Many adults, for example, will wear some type of wristwatch. Many people also will frequently wear or carry portable electronic devices, such as wireless telephones, digital music players, and personal digital assistants (PDAs). Still other types of instruments, such as pedometers, compasses, and satellite positioning devices, may be carried by individuals, e.g., during athletic activities, such as running, hiking, boating, and biking. Typically, these instruments include a mechanism, a display, and a transparent crystal or lens covering the display. With analog displays, the display often will have a dial and one or more hands that move relative to the display. Additionally or alternatively, some types of analog displays may have one or more moving dials that move below an aperture in a stationary upper dial. With digital displays, the display may have some type of electronic device that changes appearance when activated, such as liquid crystal displays (LCDs), light emitting diodes (LEDs), plasma displays, and organic light emitting displays (OLEDs).
The usefulness of most instruments, however, is limited by their visibility. For example, if the crystal covering the display becomes scratched, gouged, or otherwise damaged, then it may be difficult for the user to view the display below the crystal and/or it may be difficult to protect the underlying displays and mechanisms from damage (e.g., due to moisture, dirt, debris, impact, etc.). A variety of techniques have been developed to address these problems. For example, some instrument makers will employ a scratch-resistant material for the crystal, such as sapphire. These materials, however, typically are very expensive and are only partially resistant to scratching.